Recently, rechargeable secondary batteries are widely used as energy sources or auxiliary power devices of wireless mobile devices. In addition, secondary batteries are drawing great attraction as power sources of electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) and the like suggested as alternatives to solve air pollution caused by conventional gasoline vehicles, diesel vehicles and the like using fossil fuels.
Such a secondary battery is manufactured in a state in which an electrode assembly is mounted in a battery case together with an electrolyte solution. Depending on manufacturing method, the electrode assembly is divided into a stack-type, a folding-type, a stack-folding type and the like. In the case of the stack type or stack-folding type electrode assembly, a unit assembly has a structure in which a cathode and an anode are laminated in this order such that a separator is interposed therebetween. In order to manufacture such an electrode assembly, manufacture of a cathode and an anode is first required.
That is, in order to manufacture a unit electrode such as a cathode and anode, first, a process for notching a continuous electrode sheet, in which an electrode active material is applied to one or both surfaces thereof, at an interval of a unit electrode, is required. The notching process is generally carried out by notching a part of the electrode sheet using a press.
The press apparatus is an apparatus for processing an electrode sheet, a material to be pressed, in the form of a predetermined shape and processing is generally carried out in a continuous feeding manner.
Such a continuous feeding manner is a method in which a press simultaneously transports and presses the electrode sheet, and is characterized in that the pressed electrode sheet is continuously fed without stop.
Describing this continuous feeding manner with reference to FIG. 1, the apparatus includes a press 20 to press an electrode sheet 10 in the form of a predetermined shape and a feeder 30 to feed the electrode sheet 10 to the press 20, and the press 20 also serves as a feeder. That is, the press 20 presses the electrode sheet 10 and, at the same time, transports half of a transport length, and the stand-by feeder 30 continuously transports the electrode sheet 10 in a state that the feeder 20 transports the remaining transport length. The electrode sheet 10 is continuously transported at a predetermined rate.
However, such a continuous feeding manner can feed the electrode sheet 10 at a predetermined rate, thus enabling stable pressing of the press 20, but, since it is difficult to feed the electrode sheet at a high rate due to inertia of a mold 22 that moves together with the press 10 when the press 10 moves left and right, a problem of deterioration in production efficiency occurs, thus resulting in increase in costs.
Accordingly, there is a need for development of a novel notching device to solve these problems.